I think one of my problems is I'm using a still air incubator and as you know the temperature is not uniform. I think I'm going to buy the circulated fan kit for the incubator and hopefully this will allow me to maintain a uniform temperature.

I have a homemade incubator and the acurite one from walmart is really good. Paid around $11 for it. Plus I bought the reptile temp & humidity ones from petsmart paid $6 each. They read the same as the acurite one.

I bought a digital thermometer/hydrometer at petsmart. Its "Flukers" brand which is used for reptile tanks. It matches up with the other two thermometers so I think its pretty accurate. It costs $21. There are models made especially for incubators. I believe brinsea is the trusted brand but I have no experience with it. Most hatcherys carry it though.

I have heard the Flukers is good and I would imagine it would be the best choice as it is designed to maintain accurite temps in a similar environment to the incubator. There is one that is especially for incubators http://www.cutlersupply.com/store/item.0460.html

This one is not designed to be used inside the unit but to spot check as I understand it. You can leave it out and keep the probe inside but the batteries will run out quickly.